This invention relates to weight sorting systems for poultry, or the like.
Weight sorting systems of the type disclosed in U.S. Pat. Nos. 3,291,303 and 3,680,693, widely marketed as a selector scale system, are well known in the art. Such weight sorting systems are associated with poultry carriers rollingly supported on a fixed track and conveyed therealong by an overhead conveyor chain. A pair of adjacent weighing stations are established by a pair of vertically movable track sections aligned in a gap of the fixed track, so as to load a pair of scale beam types of weighing devices set to establish upper and lower weight limits. A load releasing latch on each carrier is tripped by a power operated release device mounted just downsteam of the weighing stations to release the load from the carrier if it is between the upper and lower weight limits. The first weighing device or station in the direction of travel establishes the upper weight limit while the lower weight limit is established at the second weighing station.
The foregoing prior art weight sorters require and include a lockout device which is rendered operative in response to detection of a load above the upper weight limit at the first weighing station, to mechanically prevent operation of the weighing device associated with the second weighing station. Thus, if the load is below the upper weight limit, the lockout device remains inactive so that if the load is above the lower weight limit, it will be detected by the second weighing device. Operation of the second weighing device then triggers the load release device. Release of the load is detected by a reset switch in order to reset the controls for another weight sorting operation.
Timely operation of the aforementioned lockout device and reset switch imposes limitations on the spacing between weighing stations and between the carriers along the conveyor path because of the distance the load must travel along the movable track sections to insure that the scale beams of the weighing devices are unbalanced for a sufficiently long time to effect the lockout and release functions. Mechanical lockout of the second weighing device and actuation of the reset switch are also sources of malfunction normally expected of separate mechanical components in a system. It is, therefore, an important object of the present invention to provide a weight sorting system of the aforementioned type that avoids the spacing limitations and eliminates use of separate mechanical lockout and reset switch devices.